Engineer, Lord Corporation, Cary, North Carolina
Pages: 13 Published: Jan 1994
A long term objective of our work is to show that the properties of an adhesive can be used as the primary formulating guide to develop adhesives that bond well to a variety of thermoplastics. It is also postulated that bond strengths would be influenced to a great extent by the rheological properties of the substrate, consequently, given a substrate, one would formulate an adhesive not so much by chemical modifications but by rheological modifications. This paper demonstrates that the bond strength of a lap shear joint at a given time and temperature can be correlated with the rheological properties of the substrate and the adhesive. In the first part of the experiments, the dynamic rheological characteristics of the substrate to be bonded were measured. This substrate was then bonded with an adhesive that cures at several different temperatures. The dynamic properties of the adhesive at these cure temperatures were measured. The bond strength at a specific temperature could be explained by by examining the rheological properties of the adhesive and the substrate. In separate experiments, it was found that the rate of bond strength development of the adhesive was largely independent of the adhesive/substrate combination once effects for the thermal conductivity of the substrate were accounted for.
modulus, adhesive, rate of bond strength development, rheology
Paper ID: STP12912S